Ratchet wrench



W. J. JOHNSON RATCHET WRENCH Dec. 4, 1956 2 Sheets-Sheet 1 Filed Jan.12, 1951 INVENTOR.

mwmmm Wdifer f Jvizizsm BY @402 W. J. JOHNSON RATCHET WRENCH Dec. 4,1956 I 2 Sheets-Sheet 2 Filed Jan. '12, 1951 mm s I v RATCHET I WalterJ. Johnson, Butfalo, N. Y., assignor to ,J. H. Willianls & Co., Buffalo,N. Y., a corporation of New York Application January 12, 1951, SerialNo. 2 (l5 ,'6 2 d 4 Claims. (Cl. 19243.1)

My. present invention relates to ratchetrnechanis'ims and aims toprovide certain improvcments'ther'ein. More particularly it relates toratchet wrenches of the type in which a driving member carriedby ahandle is opera-1 tively connected with a rotatable head or drivenmember by a. pawl and ratchet mechanism, externally, manually manpula'table means being provided for quickly effecting a reversing actionfor the wrench. v 4 I In'wrenches of the type set forth, the drivingmember usually comprises a handle which is formed with an enlargedhollow head having internal teeth, and the driven member comprises awork-engaging head having one qr in'o re pawls for coacting with theteeth in thedriving member whereby an oscillatory movement of thedriving member operates to rotate the driven member in a clock: i f wlterc'l k b d r t d n r n. the set position of the pawl or pawls. Inorder to obtaina 'fine ratchet action with such wrenches the pitch ofthe teeth must be very small, thus necessitating the driving memberbeing formed with a large number of intern al teeth, a constructionwhich is not only costly to produce but one which renders the teeth weakbecause of their :small pitch.

, An object of the present invention is to provide a ratchet wrench ofthegeneral type set forth wherein the adyan- :tages of a fine-toothedratchet wrenchis obtained without reducing the pitch or increasing thenumber of the internal teeth in thedriving member. V v

A furthe r object of the invention is to provide a wrench oflthecharacter set forth wherein apositive mechanical. shift .of, the pawlsis relied upon to manually reverse the .operation of the wrench. v

A further object of the invention is to providea ratchet wrench with aplurality of multiple-toothed pawls which :are so proportioned andcorrelated in relation tothe 'teeth on the driving member, to compensatefor wear on. the. teeth and to obtain a fuller contact of the teethunder deflection of ,the power-applying head of the wrench and, undersuch deflection, to also provide partial engagement for the normallypartially engaged pawl and? itherebyabs'orb part of the torsional loadand thus reduce the stressesin the fully engaged pawl.

. A. still further object of the invention is .to generally improve andsimplify the construction of ratchet wrenches :tolren'der. them moree'flicient in use. I

. The-foregoing and other objects of my invention notv zs'p'ecificallyenumerated I accomplish by providing .a 'ratchet wrench, comprising adriving member having an internally toothed wall and a driven member,which car-. ries a plurality of oscillatable pawls, the teeth of which::are. so formed and correlated to the'internal teeth inthe drivingmember that a multiple ratchet action will result, "i. .e., .a'ratchetaction equivalent to that provided by a .multiple of .thenumber ofteethin-the driving. member. Suchzmultiple ratch'eta'ction is preferablyobtained-by em'-- ploying a..-pair of substantially diametricallyopposed *mu'lti-toothed pawls pivotally mountediii the drivenme'mbertfor coaction with the teeth in the driving member,

2,772,753 Patented Dec. 4, 1956 I h on'oneof the pawls being disposedfor ith the'tleethon the driving member, while U ther pawl are offsetsubstantially A N in re tion ito the teeth on the driving member; ;,mens being provided for biasing the pawl te htoward engaging positionwith'the teeth in the d rivin "member. Theinvention as. a whole as wellthe va ous novel'elements and combinations will be better uh need frijrnthe detailed description which f'o o when considered in connection withthe ac.- cornpanylng idrawings'showing a preferred embodiment, d. whe nFigured is a top plan view of a ratchet wrench emy yj r 15 Fig. 23ssectlonal View taken along the plane of the qz z. a Fi -J.

'e ional view taken along the plane of the "F gif Wfractionaltopiplanview of the wrench head, part theregf being jbrolgenaway to better illustrate the relationship of parts thereof.

l i g. is a 'sect'onal mew taken substantially alongthe 25 l ne g, tw'ls'b 'ng disposed in a position to elf e'ct kwise rotation 0 th driven:inemberr J H v I V v ilar to Fig. 6 .shoiving' the v pawls d spos'edinjneutral ppsition to permit the driving er to be freely rotated eitherclockwise or counterrelative to the driven member. v "Ref ring to therawing's in the various figuresof same ref ence'characters are employedtodesthereference numeral .1 0 is ihg diameters 1 14, lflq, 1 5 alndj 16 providing shoulders 40 11;p 18 andhl9 between the; bore';portions .13and H i I M 4a and 15, ,and and 16,.respectively. The b'ore portion 13is internally'threaded to provide s c rew threads 13 ar'1dj the boreportion-14a is formed .t .h1t. eet v Th 1 0, n-v the driving member ofthe ratchet ihgat its lower end a work-engaging head or shank 23prpj'epting throughthebore portion 16 and having a socket 2 4 within.Which is usuallyv mounteda spring-impelled ball detent,(not shown);Therunner is formed with an axial recess 25 extending inwardlyfrom itstop andwith a pair of drilled recesses 26 and 27,' t'he axes of whichare disp' d the plane of a diameter of the runner and at equal radlaldistances from the axis thereof. Also formed in thetop face ofthe'runner is a recess 28 for accommodatingrastop ball 29,-the'functionof which will be'hereinafterexplained. The runner 'is also formedwithsegmental slots 30 and 31' which intersect the recesses 25, 26 and27, at right angles, which slots terminate in parallel ch'ordal wallswhich are equally spaced from a d'ia'rn'etrieal 'pIan leavingdiametrically disposed portion 3 2aiid 33 in the nature of supportsconnecting theiipper and lower portions of the runner. The corners ofsaid supporting members '3'2'and 33 whereat t hey intersect thecehtral'rcess 25 are'cha'mfered, as shown at 34, and the ir'inereiids'of said supports form parts of the wall of said" dle having a,hand-gripping axial recess 25. The gland 22 is formed with recesses 22afor accommodating a spanner.

Pivotally supported on shafts 35 and 36 mounted in the recesses 26 and27, respectively, are a pair of substantially sector-shaped pawls 37 and38, respectively, which are double ended and symmetrical with respect totheir pivotal supports. Preferably the pawls are formed with a pluralityof teeth at each end for coaction with the teeth 20 in the head, theteeth on the pawl 37 being designated 39, 39', and the teeth on the pawl38 being designated 40, 40'. The inner end of each pawl is con: stitutedby a generally flat central surface 41 and merging curved end surfaces43. The pawls 37 and 38 are mounted in diametrically opposed relationand the teeth on the corresponding ends of the pawls are selectivelynormally urged or biased toward engaging position with the teeth in thedriving member by spring-pressed means, hereinafter described, mountedin a shifter bolt 44.

The shifter bolt 44 has a lower cylindrical portion 44a of a diametercorresponding to the diameter of the axial recess 25 in the runner, saidcylindrical portion being cut away along parallel chordal planes toprovide opposite flat faces 44b, between which faces it is formed with athrough transverse cylindrical opening 440 within which is disposed ahelical spring 45 which presses a pair of balls 46 radially outward inopposite directions against the inner ends of the pawls 37 and 38. Abovethe cylindrical portion 44a the shifter bolt is formed with an annularflange 47 which rests on the top face of the runner 21 with which it isheld in rotatable engagement by an overhanging central flange 48 on thegland 22, said flange 48 also serving to hold the ball 29 in its recess28. The flange 47 is partially cut away along a chordal plane 49, asbest shown in Fig. 5, for a purpose which will be presently explained.Directly above the flange 47 the shifter bolt has a portion 50 ofreduced diameter which is also cut away along the same chordal plane 49.Projecting upwardly from the portion 50 the shifter bolt is of reduceddiameter and formed with a left-hand screw-thread 51 which is engaged bya manually operable shifter 52, herein shown as being of cruciform shapeto facilitate finger manipulation thereof. The shifter 52 is secured tothe shifter bolt by a screw 53 having a right hand thread engaging in atapped hole 54 in the top of the shifter bolt, said screw having anenlarged head 55 seating within a recess 56 in the shifter 52.

In order to obtain a fine ratchet action for the wrench withoutincreasing the number of internal ratchet teeth 20 in the head 12, Ipreferably employ an odd number of teeth in the head and mount the pawls37 and 3-8 in diametrically opposed relation so that when the teeth onone end of one of the pawls are in engagement with the ratchet teeth inthe head, for example, when the teeth 39 on the pawl 37 (Fig. 6) are insubstantial engagement with the teeth 20 in the head 12 of the drivingmember, the corresponding teeth 40 on the pawl 38 will be offsetsubstantially one-half pitch in relation to the teeth on the drivingmember; and vice versa when the teeth 40 on the pawl (Fig. 7) are insubstantial engagement with the ratchet teeth 20, the correspondingteeth 39' on the pawl 37 will be offset substantially one-half pitch inrelation to the teeth 20. Accordingly, in the use of the wrench, whenthe handle is drawn back to again engage the teeth of the pawl afterhaving rotated the driven member through an arbitrary angular distance,the teeth on the driven member may engage the teeth on either of thepawls 37 or 38 depending on whether the back angular stroke of thehandle is stopped at a point of tooth engagement between the teeth 20and the teeth on pawls 37 or 38. The same principle of operation can beaccomplished by employing an even number of teeth on the driving head inconjunction with diametrically opposed unsymmetrical oscillating pawlsthe teeth of which on the corresponding ends of the pawls are staggeredone-half pitch; or where more than two pawls are employed, by pivotallymounting them in substantially equal angular spaced relation on thedriven member about the axis thereof, with the teeth on successiveangularly spaced pawls progressively offset in relation to the teeth onthe driving member an amount equal to the tooth pitch of the teeth onthe driving member divided by the number of pawls.

In the operation of the ratchet wrench let it be assumed that it isdesired to apply a rotative force to the driven member in a clockwisedirection. To do this the shifter 52 is manually turned in acounterclockwise direction until the chordal surface 49 engages the stopball 29, as shown in Fig. 5. This action rotates the shifter bolt 44 ina counterclockwise direction in the course of which the lateral flatfaces 44b of the shifter bolt engage and move the pawls about theirpivot shafts 35, 36 while the springpressed balls 46 exert a radialoutward force again-st the inner end surfaces 41 and 43 to urge theteeth on one end of one of the pawls into engagement with the teethinthe driving head and the corresponding teeth on the other pawl towardthe teeth on the driving head, but only into partial engagement withsaid teeth because of the one-half pitch offset between said teeth onsaid latter pawl and the driv-. ing member. When it is desired toreverse the operation of the wrench, the shifter is moved in a clockwisedirection until such movement is stopped by engagement of the chordalsurface 49 with the stop ball 29, as shown in phantom in Fig. 5. In viewof the symmetrical form of the pawls and the absence of teeth betweenthe toothed ends thereof, it will be apparent that when the shifter isin an intermediate position between its stop limits, the teeth onneither end of the pawls will be in engagement with the teeth in thedriving head and, under said condition the driving head may be freelyrotated in either direction relative to the driven member withoutimparting rotation to the latter.

The formation of the teeth on each pawl end are so proportioned tocompensate for wear and thereby obtain fuller contact under deflectionof the driving member head, runner and shafts; also under deflection andwear, the partially engaged pawl teeth 40 in Fig. 6 and 39' in Fig. 7more fully engage the teeth in the head and absorb part of the primarytorsional load which reduces the stresses in the fully engaged members.The tooth formation on the pawl-s and their disposition whereby underdeflection and wear they will more fully engage the teeth in the drivinghead, follows the teaching with respect to said parts as disclosed inUnited States patent to Kress, No. 1,957,462, May 8, 1934. Under normalstress, the back face of the inoperative sides of the pawl'does notcontact the body of the driven member .but is spaced slightly therefromas will be apparent from an inspection of Figs. 6 and 7. Under suchcondition the direction of shear in the pawl shaft is substantiallyparallel to the flat faces on the parts 32 or 33 of the driven member.Under severe stress and deflection of the pawl, the back face of theinoperative sides of the pawl abuts the fiat faces on the parts 32 or 33which then prohibits the pawl from further rotation on its shaft axis.In this position all additional forces tending to rotate the pawl areabsorbed by bending of the pawl, a change in direction of shear in thepawl shaft and a compressive stress in the body of the driven member bycontact therewith of the end at the back face of the inoperative side ofthe pawl. It will also be seen from Figs. 1, 5, 6 and 7 that theinternal teeth in the driving head are eccentrically disposed in saidhead so that the thickness of the head is smallest at the end of thecenter line of the handle and progressively increases toward thejuncture of the head with the handle, a construction which alsocontributes toward influencing the engagement of the teeth on the pawland in the head caused by flexing of the handle in use. Also, the gland22 is recessed at 22b, 22c to form a bearing for the driven member 21,which bearing, in addition to maintaining axial alignment of the drivenmember separate from the body (which is distorted under stress) servesas a reinfOICiQment of the upper flange of the driven member to.

interrupt and reduce the expanding forces of the flange at the pawlshaft journals, which forces otherwise would be transmitted directly tothe unsupported mouth of the cup-shaped head 12.

From the foregoing detailed description it will be understood that Ihave provided a ratchet wrench which accomplishes the various objects ofmy invention as set forth in the opening part of this specification and,although I have specifically illustrated and described a singleembodiment of my invention, the same is to be considered as merelyexemplary and not in a limitative sense, since changes therein may bemade within the scope of mechanical and engineering skill withoutdeparting from the spirit of my invention as defined in the appendedclaims.

What I claim is:

1. In a ratchet mechanism, the combination of a driving member having aninternally toothed wall, a driven member rotatively mounted in thedriving member, two double-ended, multi-toothed pawls journaled onshafts substantially diametrically opposite each other mounted in thedriven member and parallel to the axis thereof for selective coactionwith the teeth on the driving member, the teeth on one end of one of thepawls being normally in engagement with the teeth on the driving memberwhile the teeth on the corresponding end of the other pawl are offsetone-half tooth pitch in relation to the teeth on the driving member,resilient means biasing the pawls to the aforementioned positions, ashifter bolt rotatably and coaxially mounted in the driven member andsupporting the resilient biasing means, manually operable means forrotating the shifter bolt to selectively engage the teeth on one end ofthe pawl with the teeth in the driving member and the teeth on thecorresponding end of the other pawl into offset relation, the shifterbolt having integral abutments for mechanically engaging and moving thepawls about their shafts, for reversing the operation of the wrench,when the shifter bolt is manually rotated, the driven member having ahub formed with segmental slots therein to provide pairs of flangeswithin which the shafts of the pawls are journaled, and a recessed glandmounted in the top of the driving member providing a bearing for thedriven member and serving as a reinforcement for the upper flanges tointerrupt and retard the expansive forces of the upper flanges at thepawl-shaft journals, which forces otherwise would be transmitteddirectly to the driving member.

2. In a ratchet mechanism, the combination of a driving member having abore the wall of which is formed with axially extending teeth, a drivenmember having a hub rotatably mounted in the bore of the driving member,said hub having segmental slots formed therein perpendicularly to theaxis, said slots terminating in chordal walls, a double-ended,multi-toothed pawl in each of said slots journaled on a shaft parallelto the axis of the driven member with the axes of said shafts disposedin equal angular spaced relation at the same radius from the axis of thedriven member, said pawl-s being mounted for selective coaction with theteeth on the driving member, resilient means biasing the correspondingends of the pawls toward engaging position with the teeth on the drivingmember, one end of at least one of the pawls under normal stress beingin engagement with the teeth on the driving member while the back faceof the inoperative end of said pawl is slightly spaced from the chordalwall of the slot, and wherein under severe stress and deflection of saidpawl, the back face of the inoperative end of said pawl will abut saidchordal Wall of the slot, whereby all additional forces tending torotate the pawl will be absorbed by bending of the pawl, a change indirection of the shear in the pawl shaft, and a compressive stress inthe body of the driven member by the contact therewith of the back faceof said inoperative end of said pawl with the driven member.

3. A ratchet mechanism according toclaim 2 wherein the driven member hastwo segmental slots each somewhat smaller than a semi-circle with thechordal walls of the slots parallel and equally spaced from adiametrical plane passing through a wall provided between the chordalwall surfaces and perpendicular to a diametrical plane passing throughthe pawl shafts.

4. In a ratchet mechanism, the combination of a driving member having aninternally toothed wall, a driven member rotatively mounted in thedriving member, two double ended, multi-toothed pawls journaled onshafts substantially diametrically opposite each other mounted in thedriven member and parallel to the axis thereof for selective coactionwith the teeth on the driving member, resilient means biasing the pawlsto urge the corresponding ends thereof into engagement with the teeth onthe driving member, a shifter bolt rotatably and coaxially mounted inthe driven member and supporting the resilient biasing means, manuallyoperable means for rotating the shifter bolt to selectively engage theteeth on the corresponding ends of the bolts with the teeth in thedriving member, the shifter bolt having integral abutments formechanically engaging and moving the pawls about their shafts forreversing the operation of the wrench when the shifter bolt is manuallyrotated, the driven member having a hub formed with segmental slotstherein to provide pairs of flanges within which the shafts of the pawlsare journaled, and a recessed gland mounted in the top of the drivingmember providing a bearing for the driven member and serving as areinforcement for the upper flanges to interrupt and retard theexpansible forces of the upper flanges at the pawl-shaft journals, whichforces otherwise would be transmitted directly to the driving member.

References Cited in the file of this patent UNITED STATES PATENTS1,307,485 Cunha June 24, 1919 1,957,462 Kress May 8, 1934 2,013,765Richardson Sept. 10, 1935 2,020,883 Gagne Nov. 12, 1935 2,103,556 RuebDec. 28, 1937 2,126,843 Tintera et a1 Aug. 16, 1938 2,188,846 Rueb Jan.30, 1940 2,395,681 Odlum et a1 Feb. 26, 1946 2,537,175 Viets Jan. 9,1951 2,543,509 Sandberg Feb. 27, 1951 2,544,795 Knudsen Mar. 13, 19512,571,939 Pfauser Oct. 16, 1951 2,591,993 Aijala Apr. 8, 1952 FOREIGNPATENTS 729 Great Britain Feb. 19, 1881

